Field-dependent Magnetic Anisotropy of Single Crystal Fe$_{1-x}$Ga$_{x}$ Films on ZnSe(100)*

Magnetoelastic alloys in the thin film form that are pinned to a substrate are of current interest as materials for controlled spin dynamic damping. When the single crystal magnetoelastic alloy material Fe$_{1-x}$Ga$_{x}$ (which has a large magnetostriction value in the bulk) is epitaxially deposited onto the non-magnetoelastic material ZnSe, a biaxial strain is generated at the interface because of lattice mismatch. Anisotropic mechanical strain relaxation will generate a uniaxial magnetic anisotropy in the thin film. The application of a magnetic field will modify the strain resulting in an additional field dependent uniaxial contribution. This has been demonstrated using multi-frequency, angle-dependent ferromagnetic resonance measurements on single crystal Fe$_{1-x}$Ga$_{x}$ thin films, ranging from 0{\%} to 60{\%} Ga concentration, deposited on ZnSe(001) surfaces that display a field independent cubic anisotropy while the uniaxial anisotropy is dependent on the applied field.